The digital Tach/Hour meters will keep track of engine RPMs and running time for all types of gasoline powered engines. The unit is powered by an internal lithium battery (CR2032) so no external power connections are required. The operation of the Tach/Hour meter is connected by 5 ft. insulated wire. You will wrap the rpm wire around the spark plug. The Tach/Hour meter is activated by the spark of the engine. Because the unit it activated by the spark of the engine it will keep track of the actual hours/duration of operation. This Tach/Hour meter is useful for maintenance or warranty applications for any type of gasoline powered engine.